Criminal Law · Deep dive

Drink driving — limits, defences and penalties

Drink driving is one of the most common charges ordinary New Zealanders face, with thousands of convictions every year. The technical detail of how Police process you matters far more than most people realise.

Drink driving offences are dealt with under the same criminal court framework as other offending — infringement offences at the bottom, then Categories 1, 2 and 3 of greater seriousness. Where you sit on that ladder, and whether the Police gave the right advice during your processing, will often decide the case.

The legal limits

New Zealand runs three blood alcohol concentration (BAC) limits depending on who is driving.

  • General drivers: 0.05% BAC
  • Drivers under 20: zero tolerance — no alcohol at all when driving
  • Breath and blood limits: 250mcg per litre of breath / 50mg per 100ml of blood
  • Police have authority to conduct random roadside breath testing (RBT)

Infringement notice or prosecution?

Since 2014, a driver who exceeds 250 micrograms of alcohol per litre of breath but does not exceed 400 micrograms is dealt with by infringement notice. That can mean a fine and 50 demerit points, but no conviction.

Once a driver blows over 400 micrograms per litre of breath, the Police prosecute. On conviction the typical outcome is a six-month disqualification and a fine. At high readings — over 650 micrograms of breath or 130 milligrams of blood, with lower thresholds for recent repeat offenders — the Police can also impose an immediate 28-day licence suspension at the roadside under section 95.

Technical defences — Stuart and Yang

There have been a number of recent District Court acquittals on what are properly called technical defences — defences based on the Police failing to give the correct advice during the arrest procedure. Police v Stuart and Police v Yang are the cases we keep coming back to.

Both cases turned on the wording the Police use in section J of their drink driving checklist. Section 77(3A) of the Land Transport Act requires that a driver be advised that a positive evidential breath test result could of itself be conclusive evidence to lead to that person's conviction. The checklist Police have used for years instead refers to the result being conclusive evidence "in a prosecution against" the person. Judge Collins took the view that this wording does not adequately advise the driver of the possible effect of the test. The difference is not just semantics — and these cases show that technical arguments, properly run, can and do succeed.

Penalties on conviction

On conviction, the court has a familiar set of tools.

  • Fines
  • Imprisonment for high-level or repeat offenders
  • Disqualification from driving — months to years depending on severity
  • Progressively harsher penalties for repeat offenders

Alcohol interlocks for repeat offenders

For drivers convicted of serious or repeat drink driving offences, the law allows an alcohol interlock device to be ordered for installation in the vehicle. The driver has to pass a breath test before the car will start.

For many repeat offenders this is the realistic pathway back to driving — but it has its own statutory framework and it interacts with other parts of the Land Transport Act, so the order needs to be looked at carefully at sentencing.

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Common Questions

Criminal Law FAQs.

A few criminal law-specific answers. See the full FAQ →

Should I talk to the police if they want to interview me?
Generally, no — exercise your right to silence and ask to speak with a lawyer first. There are limited exceptions (for example, providing identifying information or alibi details). Anything you say can be used against you, and what feels like a friendly chat is rarely just a chat. Contact chambers before the interview if at all possible — urgent criminal matters are treated as a priority.
What is the difference between a Judge Alone Trial and a jury trial?
A Judge Alone Trial (JAT) is heard by a District Court judge sitting without a jury — the judge decides both the law and the facts. A jury trial — typically in the High Court for serious matters, or the District Court for some Category 3 offences — has a jury of 12 deciding the facts, while the judge rules on the law and the sentence. JATs are usually quicker and cheaper, and can be the right call for technical defences. The choice between the two is a strategic decision and one of the first conversations we have.
What is a section 189A strangulation charge?
Strangulation, codified in section 189A of the Crimes Act 1961 (introduced December 2018), is the offence of intentionally or recklessly impeding another person's breathing or blood circulation by applying pressure to the throat or neck, or blocking the nose or mouth. It carries a maximum penalty of 7 years' imprisonment. Aggravating factors set out in Ackland v Police [2019] include offending in an intimate relationship, accompanying threats, loss of consciousness, multiple incidents, and breach of protection orders. This is a recognised area of our criminal practice.
What is the Clean Slate Act and do I qualify?
The Criminal Records (Clean Slate) Act 2004 lets people with minor criminal histories avoid disclosing them in most situations — once they have gone seven years without a new conviction, served no custodial sentence, completed all sentences and fines, and have no excluded offence types. There are exceptions: roles working with children or vulnerable people, immigration applications, and certain professional licences may still require full disclosure.

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